JPS60171015A - Electric heater of electric pot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electric heating appliances such as electric water heaters used in general households.

Conventional configurations and their problems In recent years, temperature control methods for electric heating appliances with heating elements, such as electric rice cookers and electric pots, have replaced the conventionally used thermostats and thermal reed switches, and are now using sensors such as thermistors. The so-called electronic control method, which uses control components such as semiconductor power control elements such as thermal elements, bidirectional cy-risks, and transistors, has been adopted because of its high temperature control accuracy.

Electric heating appliances such as an electric water heater shown in FIG. 1 are examples of appliances using this electronic control system.

To briefly explain its structure, 1 is an outer body, 2 is a container disposed inside the outer body 1, and 3 and 4 are temperature sensing elements including a heating element and a thermistor attached to the outer bottom surface of the container 2. , 5 is a hook part screwed and fixed to the bottom surface of the outer body 1 together with a back plate 6, and this hook part 6 has a concave shape whose inner wall extends to above the lower opening of the outer body 1 and projects upward. , a cooling plate 8 having a semiconductor power control element 7 attached thereto connected to the heating element 3, and a control board 9 having control parts such as transistors and resistors attached to the upper inner surface thereof, with the component mounting surface facing downward. Fixed with screws.

Further, the hook portion 6 is provided with an insertion hole 5a, and the lead wires of the heating element 3, the temperature sensing element 4, etc. are inserted through the insertion hole 5a.
It is connected to the semiconductor power control element 7 and the control board 9 through L. 1o is a heat shield plate attached to the upper surface of the hook portion 6.

In the conventional configuration described above, when the heating element 3 is energized, the current flowing through the heating element 3 also flows to the semiconductor power control element 7 and generates heat, but since the heat is radiated by the cooling plate 8, the semiconductor power Although an excessive temperature rise of the control element itself can be avoided, the surrounding temperature rises due to the heat released from the cooling plate 8. In this case, the cooling plate 8 and the control board 9 are attached to the upper inner surface of the hook 5, so even if ventilation holes are provided on the upper inner surface of the hook 5, ventilation is poor, or the upper surface of the hook 6 is Since a heat shield plate is attached to prevent radiant heat from the heating element 3, the ventilation is also poor, and therefore the area near the control board 9 attached to the upper inner surface of the hook part 6 traps heat and the temperature rises. As a result, semiconductor elements such as transistors attached to the control board 9 are exposed to excessively high temperatures, which poses a risk of malfunction or damage.

In addition, since the cooling plate 8 and the control board 9 to which the semiconductor power control device 7 is attached are attached to the upper inner surface of the armature part 6 in substantially the same plane, a part with a large planar area is required.
As a result, even though it can be installed in electric rice cookers and electric pots that have a relatively large surface space, the size of the cooling plate has been reduced for electric heating appliances that have a relatively small surface space, such as electric water heaters. There is a problem in that it is difficult to install the device by installing the device.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems.It is possible to reduce the temperature rise of the control board, and to reduce the size of the cooling plate and control board even in electric heating appliances such as electric water heaters that require a relatively small plane space. The object of the present invention is to provide an electric heating appliance such as an electric water heater that can be installed without forcibly reducing its size.

Structure of the Invention In order to achieve the above object, an electric heating appliance such as an electric water heater according to the present invention has a cooling plate attached to the bottom of the container, on which a semiconductor power control element is attached for controlling the supply of electricity to the heating element attached to the bottom of the container. A control board equipped with a control component that provides a control signal to the semiconductor power control element is disposed below the cooling plate. According to this configuration, control components that are sensitive to heat can be removed. The temperature rise of the equipped control board can be minimized by using the cooling plate, and as a result, the control parts can be thermally protected, and the flat space is small, so it is possible to minimize the temperature rise of the installed control board. This allows for the installation of

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, 11 is the outer body, 12 is the outer body 11
The spout is attached to the top of the spout, and its inner step supports a bottomed cylindrical container 13 made of metal such as stainless steel. Reference numeral 14 denotes an upper lid unit that closes the upper opening of the container 13, and this upper lid unit 14 includes a pressing member 16.
The device is configured so that the material to be heated (water) in the container 13 is discharged through the discharge port 16 by forcefully feeding air into the container 13 using a built-in pump (not shown). Further, a temperature-sensing element 17 such as a thermistor is attached to approximately the center of the outer bottom surface of the container 13, and a heating element 18 is located around the outer periphery of the temperature-sensing element 17 and on the outer bottom surface of the container 13. installed.

19.1d is a pair of fittings fixed to the outer bottom surface of the container 13 and extending downward; these fittings 19, 19'
has the first tongue portions 192L, 19&/ on the upper side and the second tongue portions on the lower side.
tongue portions 19b and 19b' are formed in the horizontal direction. This semiconductor power control element 2o is a semiconductor power control element made of a bidirectional thyristor (Try Book) etc. that controls the energization to the 20Fi heating element 18. This semiconductor power control element 2o is connected to a cooling plate 21 made of a material with good thermal conductivity such as aluminum. The cooling plate 2'1 is screwed and fixed, and the cooling plate 2'1 is located below the bottom of the container 13, and is attached to the first tongue part 1 of the mounting bracket 19, 19'.
9&.

It is screwed and fixed to an insulating member 22, 22' made of a heat-resistant electrically insulating material fixed to the lower surface of 19&/.

23 is the second tongue portion 19b of the mounting fittings 19, 19'.

19g, and is equipped with a control component 23& such as a transistor on the lower surface side which provides a control signal to the semiconductor power control element 2o according to a signal from the temperature sensing element 17. This control board 23 is attached to the cooling plate 21. It is located below. 24 is a back cover that closes the lower opening of the outer body 11;
This back plate 24 is provided with a plurality of vent holes 24&, and this back plate 24 is provided with the mounting metal fittings 19&. It is screwed onto the IC/. 26, the radiant heat of the heating element 18 is directly transmitted to the cooling plate 21.
This is a heat shield plate placed so that it does not hit the area.

The operation in the above configuration will be explained. When the heating element 18 is energized, the current flowing through the heating element 18 also flows to the semiconductor power control element 20 to generate heat, and this heat is released from the cooling plate 21 to warm the surrounding air. Since this warmed air has a lower specific gravity, it moves upward through the gap between the outer body 11 and the container 13. As a result, the control board 2
The temperature rise around 3 is small. Further, since the semiconductor power control element 20 is located below the heating element 18 which generates the largest amount of heat, the temperature rise thereof can be reduced for the same reason as described above.

Effects of the Invention As described above, according to the present invention, a cooling plate equipped with a semiconductor power control element for controlling energization to the heating element is disposed below the bottom of the container, and below the cooling plate, the above-mentioned Since a control board equipped with control components that provide control signals to the semiconductor power control element is provided, the temperature rise of the control board equipped with heat-sensitive control components is minimized by the action of the cooling plate. As a result, it is possible to thermally protect the control components, and since the cooling plate and control board are arranged vertically, it is possible to use electric heating appliances such as electric water heaters that require a relatively small planar space. Even in this case, it is possible to attach the cooling plate and the control board without forcibly downsizing them.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the main part configuration of a conventional electric heating appliance, and FIG. 2 is a partially cutaway vertical cross-sectional view showing an electric water bath d1) which is an embodiment of the present invention. 13...Container, 18...Heating element, 2o
・River: Semiconductor power control element, 21: Cooling plate, 23: Control board, 23a: Control component. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] A container for accommodating an object to be heated, a heating element attached to the lower part of the container, and a semiconductor power control element for controlling energization to the heating element. An electric heating appliance, such as an electric water heater, comprising an attached cooling plate and a control board equipped with a control component that provides a control signal to the semiconductor power control element below the cooling plate.